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Chakouch M.K.,CNRS Biomechanical Engineering Laboratory | Charleux F.,ACRIM Polyclinique Saint COme | Bensamoun S.F.,CNRS Biomechanical Engineering Laboratory
PLoS ONE | Year: 2015

Background Pathologies of the muscles can manifest different physiological and functional changes. To adapt treatment, it is necessary to characterize the elastic property (shear modulus) of single muscles. Previous studies have used magnetic resonance elastography (MRE), a technique based on MRI technology, to analyze the mechanical behavior of healthy and pathological muscles. The purpose of this study was to develop protocols using MRE to determine the shear modulus of nine thigh muscles at rest. Methods Twenty-nine healthy volunteers (mean age = 26 ± 3.41 years) with no muscle abnormalities underwent MRE tests (1.5 T MRI). Five MRE protocols were developed to quantify the shear moduli of the nine following thigh muscles at rest: rectus femoris (RF), vastus medialis (VM), vastus intermedius (VI), vastus lateralis (VL), sartorius (Sr), gracilis (Gr), semimembranosus (SM), semitendinosus (ST), and biceps (BC). In addition, the shear modulus of the subcutaneous adipose tissue was analyzed. Results The gracilis, sartorius, and semitendinosus muscles revealed a significantly higher shear modulus (μ-Gr = 6.15 ± 0.45 kPa, μ- Sr = 5.15 ± 0.19 kPa, and μ- ST = 5.32 ± 0.10 kPa, respectively) compared to other tissues (from μ- RF = 3.91 ± 0.16 kPa to μ-VI = 4.23 ± 0.25 kPa). Subcutaneous adipose tissue had the lowest value (μ-adipose tissue = 3.04 ± 0.12 kPa) of all the tissues tested. Conclusion The different elasticities measured between the tissues may be due to variations in the muscles' physiological and architectural compositions. Thus, the present protocol could be applied to injured muscles to identify their behavior of elastic property. Previous studies on muscle pathology found that quantification of the shear modulus could be used as a clinical protocol to identify pathological muscles and to follow-up effects of treatments and therapies. These data could also be used for modelling purposes. © 2015 Chakouch et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

Bensamoun S.F.,Compiegne University of Technology | Dao T.T.,Compiegne University of Technology | Charleux F.,ACRIM Polyclinique Saint COme | Ho Ba Tho M.-C.,Compiegne University of Technology
Journal of Musculoskeletal Research | Year: 2013

The objective is to estimate the vastus medialis (VM) muscle force from multifrequency magnetic resonance elastography (MMRE) tests and to different rheological models (Voigt and springpot). Healthy participants (N = 13) underent multifrequency (70, 90 and 110 Hz) magnetic resonance elastography MMRE tests. Thus, in vivo experimental elastic (μ) properties of the VM in passive and active (20% MVC) conditions ere characterized. Moreover, the muscle viscosity (η) as determined ith Voigt and springpot rheological models, in both muscle states. Subsequently, the VM muscle forces ere calculated ith a generic musculoskeletal model (OpenSIM) here the active and passive shear moduli (μ) ere implemented. The viscosity measured ith the to rheological models increased hen the muscle is contracted. During the stance and the sing phases, the VM tensile forces decrease and the VM force as loer ith the springpot model. It can be noted that during the sing phase, the muscle forces estimated from springpot model shoed a higher standard deviation compared to the Voigt model. This last result may indicate a strong sensitivity of the muscle force to the change of active and passive contractile components in the sing phase of gait. This study provides for the first time an estimation of the muscle tensile forces for loer limb, during human motion, from in vivo experimental muscle mechanical properties. The assessment of individualized muscle forces during motion is valuable for finite element models, increasing the patient specific parameters. This novel muscle database ill be of use for the clinician to better elucidate the muscle pathophysiology and to better monitor the effects of the muscle disease. © 2013 orld Scientific Publishing Company.

Chakouch M.K.,CNRS Biomechanical Engineering Laboratory | Pouletaut P.,CNRS Biomechanical Engineering Laboratory | Charleux F.,ACRIM Polyclinique Saint COme | Bensamoun S.F.,CNRS Biomechanical Engineering Laboratory
Journal of Magnetic Resonance Imaging | Year: 2016

Purpose To measure the viscoelastic properties of passive thigh muscles using multifrequency magnetic resonance elastography (MMRE) and rheological models. Materials and Methods Four muscles in five volunteers underwent MMRE tests set up inside a 1.5T magnetic resonance imaging (MRI) scanner. Compression excitation was generated with a driver attached around the thigh, and waves were generated at 70, 90, and 110 Hz. In vivo experimental viscoelastic parameters (G(ω) = G′ + i Gâ€) were extracted from the wavelength and attenuation measurements along a local profile in the direction of the wave's displacement. The data-processing method was validated on a phantom using MMRE and RheoSpectris tests. The complex modulus (G(ω)) related to elasticity (μ) and viscosity (η) was then determined using four rheological models. Results Zener was the best-fit model (χ â0.35 kPa) for the rheological parameters of all muscles. Similar behaviors for the elastic components for each muscle were found for the Zener and springpot models. The gracilis muscle showed higher elastic values (about 2 kPa) in both models compared to other muscles. The α-values for each muscle was equivalent to the ratio Gâ€;/G′ at 90 Hz. Conclusion MMRE tests associated with data processing demonstrated that the complex shear modulus G(ω) of passive muscles could be analyzed using two rheological models. The viscoelastic data can be used as a reference for future assessment of muscular dysfunction. © 2015 Wiley Periodicals, Inc.

Leclerc G.E.,CNRS Biomechanical Engineering Laboratory | Charleux F.,ACRIM Polyclinique Saint COme | Ho Ba Tho M.-C.,CNRS Biomechanical Engineering Laboratory | Bensamoun S.F.,CNRS Biomechanical Engineering Laboratory
Computer Methods in Biomechanics and Biomedical Engineering | Year: 2015

Magnetic resonance elastography (MRE), based on shear wave propagation generated by a specific driver, is a non-invasive exam performed in clinical practice to improve the liver diagnosis. The purpose was to develop a finite element (FE) identification method for the mechanical characterisation of phantom mimicking soft tissues investigated with MRE technique. Thus, a 3D FE phantom model, composed of the realistic MRE liver boundary conditions, was developed to simulate the shear wave propagation with the software ABAQUS. The assumptions of homogeneity and elasticity were applied to the FE phantom model. Different ranges of mesh size, density and Poisson's ratio were tested in order to develop the most representative FE phantom model. The simulated wave displacement was visualised with a dynamic implicit analysis. Subsequently, an identification process was performed with a cost function and an optimisation loop provided the optimal elastic properties of the phantom. The present identification process was validated on a phantom model, and the perspective will be to apply this method on abdominal tissues for the set-up of new clinical MRE protocols that could be applied for the follow-up of the effects of treatments. © 2013, © 2013 Taylor & Francis.

Debernard L.,CNRS Biomechanical Engineering Laboratory | Robert L.,ACRIM Polyclinique Saint COme | Charleux F.,ACRIM Polyclinique Saint COme | Bensamoun S.F.,CNRS Biomechanical Engineering Laboratory
Muscle and Nerve | Year: 2013

Introduction: Characterization of muscle elasticity will improve the diagnosis and treatment of muscle disorders. The purpose is to compare the use of magnetic resonance elastography (MRE) and ultrasound elastography (USE) techniques to elucidate the MRE cartography of thigh muscles. Methods: Both elastography techniques were performed on 5 children and 7 adults. Quantitative (MRE) and qualitative (USE) cartographies of muscle elasticity, as a function of muscle state and age, were obtained with shear waves and manual compression of the ultrasound probe, respectively. Results: Similar cartographies of muscle elasticity were obtained with the 2 methods. The combination of both imaging techniques results in an improved depiction of the physiological changes associated with muscle state and age. Conclusions: This study demonstrates the feasibility of MRE for use as a clinical tool in the characterization of neuromuscular pathologies and for assessing the efficacy of specific treatments for muscle related diseases. © 2012 Wiley Periodicals, Inc.

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